1. Field of the Invention
Chain turbines are designed to develop power from the falling and running water of rivers. Such chain turbines rotatably positioned within a river are capable of efficiently converting running water or vertical waterfalls into rotational energy.
The chain turbine principle is similar to that of reaction-type turbines, except that the deflection buckets are not placed upon a runner encircling a shaft, rather, the deflection buckets are attached to two closed loop chains which extend across the water source. Thus, the work exerted by the river is developed simultaneously at all deflection buckets in the river as opposed to the use of standpipe jet acting upon a few buckets supported upon a runner in conventional turbines.
2. The Prior Art
Earlier patents such as RANDMETZ U.S. Pat. No. 1,749,506, ROMERO U.S. Pat. No. 3,542,485 and SCHMELLER U.S. Pat. No. 3,882,320 have utilized the principle of elongated water wheels. A series of paddles or vanes is attached to two endless chains which follow the direction of the current. The surface less than each paddle faces the stream current at an angle of 90 degrees. The moving current pushes against the surface of each paddle and urges the paddle to move with the current.
Elongated water wheels are inefficient. Since the vanes are supported one behind the other upon the chains, only the first vane directly faces the current and receives the full thrust of the current. The second vane, which is in the wake of the first vane receives less thrust, the third vane still less, and so on.
It is submitted that DAVIS U.S. Pat. No. 4,134,469 would be relatively inefficient due to the drag created by the action of the wind on the returning buckets
PATTON U.S. Pat. No. 4,494,008 addresses the problem of drag by separating his chains which are angled, such that each side moves in a separate trough, thus, the wind strikes one side of the vane only and does not interfere with the side of the returning vanes. However, it is submitted that the wind would strike only a portion of the vanes penetrating very little, or not at all, because the bottom of the trough will interfere with its passage. The result is that the wind will act upon only the top of the vanes rather than on the entire surface of the vanes.
LI U.S. Pat. No. 4,303,834, uses airfoils, attached to two cables suspended transversely as a windmill to produce power. The airfoils are mechanically adjusted as they rotate. LI's device is an elongated propeller-type windmill.
The conventional chain turbine exhibits an efficiency of approximately 60%. However, this efficiency can be enhanced by increasing the velocity of the water as a result, for example, of narrowing a river, or by utilizing a greater number of buckets, so as to increase the total surface area of the paddles